Cobalt-Catalyzed Cyclization of N-Methoxy Benzamides with Alkynes using an Internal Oxidant through C-H/N-O Bond
Ganesan Sivakumar1, Arjun Vijeta1, Masilamani Jeganmohan2
1Department of Chemistry, Indian Institute of Science Education and Research, Pune, 411021, India.
Abstract:
The cyclization of substituted N-methoxy benzamides with alkynes in the presence of an easily affordable cobalt complex and NaOAc provides isoquinolone derivatives in good to excellent yields. The cyclization reaction is compatible with a range of functional group-substituted benzamides, as well as ester- and alcohol-substituted alkynes. The cobalt complex [Co(III) Cp*(OR)2 ] (R=Me or Ac) serves as an efficient catalyst for the cyclization reaction. Later, isoquinolone derivatives were converted into 1-chloro and 1-bromo substituted isoquinoline derivatives in excellent yields in the presence of POCl3 or PBr3 .
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